i want to know why our tongue has the different area for fell the different taste... ?why do not all of the tongue surface can fell all kind of taste...?
do not said that it is for eat "yeak.." drug. so that we do not get a "bad" fell when we are put it at the midle of our tongue surface.

The pallatine area is more sensitive to sour and bitter tastes and less senzitive to sweet and salty. the pharynx and epiglottis are equally senzitive to all tastes
As for why are the taste buds lcoated in specialised areas... I really have no idea why they evolved that way. sorry... i'll ask my girlfriend

"As a biologist, I firmly believe that when you're dead, you're dead. Except for what you live behind in history. That's the only afterlife" - J. Craig Venter